# Module `AcyclicGraph.Make`

### Parameters

• `Point : Point`

### Signature

`type t`
`val empty : t`
`val check_invariants : required_canonical:(Point.t -> bool) -> t -> unit`
`exception ``AlreadyDeclared`
`val add : ?⁠rank:int -> Point.t -> t -> t`

All points must be pre-declared through this function before they can be mentioned in the others. NB: use a large `rank` to keep the node canonical

`exception ``Undeclared of Point.t`
`val check_declared : t -> Point.Set.t -> unit`
raises Undeclared

if one of the points is not present in the graph.

`type 'a check_function`` = t -> 'a -> 'a -> bool`
`val check_eq : Point.t check_function`
`val check_leq : Point.t check_function`
`val check_lt : Point.t check_function`
`val enforce_eq : Point.t -> Point.t -> t -> t`
`val enforce_leq : Point.t -> Point.t -> t -> t`
`val enforce_lt : Point.t -> Point.t -> t -> t`
`val constraints_of : t -> Point.Constraint.t * Point.Set.t list`
`val constraints_for : kept:Point.Set.t -> t -> Point.Constraint.t`
`val domain : t -> Point.Set.t`
`val choose : (Point.t -> bool) -> t -> Point.t -> Point.t option`
`val sort : (int -> Point.t) -> Point.t list -> t -> t`

`sort mk first g` builds a totally ordered graph. The output graph should imply the input graph (and the implication will be strict most of the time), but is not necessarily minimal. The lowest points in the result are identified with `first`. Moreover, it adds levels `Type.n` to identify the points (not in `first`) at level n. An artificial constraint (last first < mk (length first)) is added to ensure that they are not merged. Note: the result is unspecified if the input graph already contains `mk n` nodes.

`val pr : (Point.t -> Pp.t) -> t -> Pp.t`
`val dump : (constraint_type -> Point.t -> Point.t -> unit) -> t -> unit`